Pilot experiments are proposed to test the functional integrity of fetal cortical tissue implanted to replace damaged areas of the visual cortex. Infant rats will receive lesions of the visual cortex, and donor occipital cortices, harvested from fetal rats, will be implanted into the cavity created by the lesion. Electrophysiological recording methods will be applied to the animals in order to test: 1) visual responsivity of the implants; 2) order of the visual field map in the implants; and 3) receptive field properties of implant neurons. These experiments are necessary to test the possibility that transplantation is an appropriate therapeutic strategy to restore visual function after brain damage.